8-mirror microlithography projection objective

Abstract

A projection objective provides a light path for a light bundle from an object field in an object plane to an image field in an image plane. The projection objective includes a first mirror (S 1 ), a second mirror (S 2 ), a third mirror (S 3 ), a fourth mirror (S 4 ), a fifth mirror (S 5 ), a sixth mirror (S 6 ), a seventh mirror (S 7 ), and an eighth mirror (S 8 ). The light bundles includes light with a wavelength in a range of 10-30 nm. The light is provided via the eight mirrors, and in the light path exactly one intermediate image of the object field is provided.

1. A projection objective that provides a light path for a light bundle from an object field in an object plane to an image field in an image plane, said projection objective comprising:
 a first mirror (S 1 ); 
 a second mirror (S 2 ); 
 a third mirror (S 3 ); 
 a fourth mirror (S 4 ); 
 a fifth mirror (S 5 ); 
 a sixth mirror (S 6 ); 
 a seventh mirror (S 7 ); and 
 an eighth mirror (S 8 ), 
 wherein said light bundle includes light with a wavelength in a range of 10-30 nm, 
 wherein said light path is provided via said eight mirrors, and 
 wherein in said light path exactly one intermediate image of said object field is provided. 
 
   
   
     2. The projection objective of  claim 1 , further comprising a diaphragm (B) in said light path between said object plane and said image plane. 
   
   
     3. The projection objective of  claim 2 , wherein said diaphragm (B) is circular or nearly circular. 
   
   
     4. The projection objective of  claim 2 , wherein said diaphragm is arranged on said second mirror. 
   
   
     5. The projection objective of  claim 1 , wherein said intermediate image is situated between said fifth mirror and said sixth mirror. 
   
   
     6. The projection objective of  claim 1 ,
 wherein said image field represents a segment of a ring field, 
 wherein said segment has an axis of symmetry and an extension in a direction of said axis of symmetry, and 
 wherein said extension has a dimension of greater than or equal to 2 mm. 
 
   
   
     7. The projection objective of  claim 6 ,
 wherein said light bundle has a chief ray of a field point that lies on said axis of symmetry and in a center of said object field, and 
 wherein said chief ray has an angle of incidence less than 26° on all said mirrors (S 1 , S 2 , S 3 , S 4 , S 5 , S 6 , S 7 , S 8 ). 
 
   
   
     8. The projection objective of  claim 1 , wherein said projection objective has a numerical aperture NA greater than 0.2 on an image side. 
   
   
     9. The projection objective of  claim 1 , wherein said projection objective has a numerical aperture NA greater than 0.2 and less than 0.5. 
   
   
     10. The projection objective of  claim 1 , wherein said projection objective has an rms wavefront error of less than 0.030λ at a wavelength of 13.0 nm. 
   
   
     11. The projection objective of  claim 1 , wherein said projection objective has a distortion of less than or equal to 1 nm. 
   
   
     12. The projection objective of  claim 1 , wherein said mirrors of said projection objective comprise multilayer systems of Mo/Be. 
   
   
     13. The projection objective of  claim 1  wherein said mirrors of said projection objective comprise multilayer systems of Mo/Si. 
   
   
     14. The projection objective of  claim 1 , wherein said eighth mirror is concave. 
   
   
     15. The projection objective of  claim 1 , wherein said seventh mirror is convex. 
   
   
     16. The projection objective of  claim 1 , wherein said fifth mirror is concave. 
   
   
     17. A projection exposure system, comprising:
 the projection objective of  claim 1 ; 
 a source of said light bundle; 
 an illumination device that partially collects said light bundle and further conducts said light bundle to illuminate a ring field; 
 a mask that bears a structure or pattern on a support system, wherein said mask is arranged in a plane of said ring field, and wherein said projection objective images an illuminated part of said mask in said image field; and 
 a light-sensitive substrate on a support system, wherein said light-sensitive substrate is arranged in said image field. 
 
   
   
     18. A device manufacturing method comprising:
 employing the projection exposure system of  claim 17 , to provide a projection beam from said source and said illumination system; 
 using said mask to endow said projection beam with said pattern in a cross-section of said projection beam; and 
 using said projection objective to project said projection beam with said pattern onto a target portion of said light-sensitive substrate.